It's because of the rumours surrounding Idris Elba as a candidate to take over the role.

Mind you, in the modern British context it could make sense. The series Spooks has broken the mould of the "old boys' club" imagery of the classic MI-5/MI-6 already - with a lot of key female or non-caucasian personnel in the secret services. Le Carré has moved on too, not that he ever really lacked good female characters in the service, unlike the stereotypical women of the Bond franchises (books and movies) . I doubt the British public would have that much of a problem with a British super agent character, especially one with not much realism anyway, being of non non-English descent, as long as he's unmistakably British where the classic Bond traits are concerned, and played by a British actor. If they were to go "retro" this wouldn't make sense, but it doesn't really make sense to "go retro" anyway. One of the characteristics of the Bond franchise has always been to adopt the "zeitgeist". For all the fact they're totally over the top and bathed in luxury, the Bond films have always been interesting mirrors of the world-view of their time, notably of what people of each decade considered "entertaining" or fascinating, and what they fear as well (and that's why the "war on terror" era Bonds are so grim). So a black Bond after a female M? Why not, if the actor can pull off the essence of the character?

I suspect the British public would have much less of a problem accepting Elba as Bond than they would have with a non-British actor playing the part, especially an American actor.